Design

Sampling of epithelial lining fluids or pulmonary edema fluids from patients with acute lung injury (ALI) or related diseases was performed. Plasma samples were obtained from them at the time of disease onset or later. G2F concentrations were determined by immunoassay constructed by ourselves.

Results

We found a significantly higher amount of G2F in pulmonary edema and epithelial lining fluids of patients with ALI, as compared with those with the other respiratory diseases. Their plasma levels were also elevated significantly early at the onset of ALI (mean ± SD; 147 ± 82 ng/ml in non-surviving and 90 ± 56 in surviving patients) as compared with those in the patients with cardiogenic pulmonary edema (59 ± 36) or idiopathic pulmonary fibrosis (37 ± 17), indicating alveolar epithelium rapidly secrete laminin-5 in ALI. At 5 days after onset, non-surviving patients maintained higher plasma concentrations (152 ± 84), but in contrast, the levels in surviving patients declined (71 ± 35), suggesting secretion of laminin-5 was suppressed, associated with recovery from ALI.

Conclusion

Circulating G2F may be a biomarker for alveolar laminin-5 secreted early at disease onset in ALI, potentially regulating alveolar re-epithelialization.